The present invention relates to an in-vehicle wireless charging system.
A wireless charging device transmits power to a charged device in a wireless manner to charge the charged device (refer to, for example, Japanese Laid-Open Patent Publication No. 2008-5573). More specifically, the charging device includes a primary coil, and the charged device includes a secondary coil. A power transmission pad is formed on an upper surface of the charging device. The charged device is set on the power transmission pad. When excited, the primary coil generates low-frequency radio waves (electromagnetic waves), which induce power at the secondary coil. The power charges a battery that is incorporated in the charged device.
The wireless charging device performs polling to determine whether or not the charged device has been set on the power transmission pad before charging the charged device. The wireless charging device starts charging the charging device after having determined through polling that the charged device has been set on the power transmission pad (refer to, for example, Japanese Laid-Open Patent Publication No. 2010-259172).
Wireless charging devices for use in vehicles are being developed so that portable terminals, or charged devices, can be charged in the vehicles. When a wireless charging device is installed in a vehicle, a user may forget and leave the portable terminal on the power transmission pad of the wireless charging device. In this case, it is desirable that a warning be generated to notify the user that the portable terminal is being left in the vehicle. Such a warning can be generated, for example, when the wireless charging device performs polling and detects the presence of the portable terminal on the power transmission pad as the user stops the engine and opens the door to leave the vehicle. However, this would result in the wireless charging device requiring an additional warning means such as a buzzer. Further, in addition to information such as whether the headlights are left on, the vehicle will also be required to obtain information such as whether the door is open or closed for the wireless charging device. This may result in complex wiring and control.